Some words become a part of our collective lexicon with such zeitgeist that it's hard to believe there was ever a time when they weren't part of the English language. And some are so definitive of an era that simply seeing them listed next to a year immediately brings you back to that time and a place — and the movies and songs that then dominated pop culture. Thanks to Merriam-Webster's new Time Traveler, now we can all travel back to a specific year with a single click and a host of dictionary entries definitive of the year they were made official.

It's hard to believe now that we never had a word for brain freeze before 1991, despite the 1950s popularity of milkshakes and soda jerks — or that we were talking about "first world problems" as far back as 1979, long before #hashtags.

Take a trip down memory lane with us —or simply look up the words that were entered the year you were born, married, graduated high school/college, etc. —with the new Merriam-Webster Time Traveler tool.

Here are two to three of our favorite words, listed by the year they were entered into the dictionary: